This invention relates to the manufacture of thiobiscarbamates having the formula ##STR1## wherein R.sub.1, is methyl, ethyl, n-propyl, isopropyl, n-butyl or isobutyl and ##STR2## wherein R.sub.2 is methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, or CH.sub.3 S(CH.sub.3).sub.2 C-- and R.sub.3 is H or CH.sub.2 X where X is --SCH.sub.3, ##STR3## These biscarbamate compounds are known to have pesticidal activity.
U.S. Pat. No. 4,004,031 discloses a method of making these compounds involving simultaneous reaction of carbamate, base, and sulfur chloride (SCl.sub.2 or S.sub.2 Cl.sub.2). A disadvantage of this prior art method is its relatively low yield of products and high production of undesirable bi-products.